In a rotary press, the circumferential length of the printing plate is a parameter which limits the format or the printing length of the product to be printed. In order to increase the flexibility of the press, it is necessary to allow a variation of the printing length or a variation of format.
In order to modify the circumferential length of a cylinder having a fixed radius in a press, open adaptation sleeves having different thicknesses can be mounted on a hub. A sleeve of this type is, for example, disclosed in the application WO2005/014286 by the same applicant.
The production of a tension mechanism which is intended to tension such an open sleeve around a cylindrical hub is complex owing to the need to prevent the top and bottom edges of the sleeve from being raised from the hub under the effect of the tensile force.
Furthermore, it is known to expand a closed adaptation sleeve by means of a cushion of air in order to be able to mount it on the hub of the press. However, the expansion of a closed sleeve requires very great pressure or involves the use of a sleeve which is both resilient and incompressible, material properties which are generally incompatible.